Delta-sigma converter with pm/fm non-linear loop

Abstract

A device, system and method for improvement of analog/digital conversion. An improved delta sigma-converter including a phase or frequency modulation and demodulation, is used. The improved delta sigma-converter obtains higher gains than traditional Delta Sigma converter, preserving or improving the oversampling and noise shaping gains of these converters.

1 . A signal processing device for non-linear analog-to-digital converting of an analog input signal into a digital output signal, comprising a Delta-Sigma, DS, converter, the DS converter comprising a subtraction unit, an integration unit, a quantization unit and a delay unit, the device comprises:
 a phase modulator, PM, in the feed-forward branch of the DS converter for performing phase modulation of either the signal integrated by the integration unit or the signal quantized by the quantization unit, and a phase demodulator in series with the delay unit in the feedback branch of the DS converter, where the phase demodulator is the corresponding demodulator to the phase modulator, performing the inverse function of the modulation performed by the phase modulator in the feed-forward branch or   a frequency modulator, FM, in the feed-forward branch of the DS converter for performing frequency modulation of either the signal integrated by the integration unit or the signal quantized by the quantization unit, and a frequency demodulator in series with the delay unit in the feedback branch of the DS converter, where the frequency demodulator is the corresponding demodulator to the frequency modulator, performing the inverse function of the modulation performed by the frequency modulator in the feed-forward branch.   
     
     
         2 . The device according to  claim 1  where the phase modulator or the frequency modulator is connected in series with the quantization unit and where the output of the phase modulator or the frequency modulator is connected to the input of the quantization unit and where the output of the quantization unit is the digital output signal of the device. 
     
     
         3 . The device according to  claim 1 , where the phase modulator or the frequency modulator is connected in series with the integration unit and where the input of the phase modulator or the frequency modulator is connected to the output of the integration unit. 
     
     
         4 . The device according to  claim 1 , where the phase modulator or the frequency modulator is connected in series with the subtraction unit, the integration unit and the quantization unit of the DS converter and where the input of the phase modulator or the frequency modulator is connected to the output of the integration unit, the output of the phase modulator or the frequency modulator is connected to the input of the quantization unit and where the output of the subtraction unit is connected to the input of the integration unit. 
     
     
         5 . The device according to  claim 1 , where the input of the phase demodulator or the frequency demodulator is connected to the output of the quantization unit. 
     
     
         6 . The device according to  claim 1 , where the output of the phase demodulator or the frequency demodulator is connected to the input of the delay unit and the output of the delay unit is the input of a subtraction unit. 
     
     
         7 . The device according to  claim 1 , where the device further comprises a low pass filter, where the output of the phase demodulator or the frequency demodulator is connected to the input of the delay unit, where the input of the low pass filter is connected to the output of the delay unit and where the output of the low pass filter is an input of the subtraction unit. 
     
     
         8 . The device according to  claim 1 , the device further comprising a sample and hold unit which processes the analog input signal at a selected sampling frequency and where the resulting sampled signal is an input of the subtraction unit of the DS converter. 
     
     
         9 . The device according to  claim 1 , where the analog input signal is an audio signal, a video signal and audio-video signal or any type of electronic signal. 
     
     
         10 . The device according to  claim 1 , where the output of the phase modulator or the frequency modulator includes an in-phase component and a quadrature component. 
     
     
         11 . A system which comprises a device according to  claim 1 , the system further comprising a pulse shaping or a digital/analog converter and where the output of the device is connected to the input of the pulse shaping or the digital/analog converter. 
     
     
         12 . A system according to  claim 11 , the system further comprising and in-phase/quadrature modulator and where the output of the pulse shaping or the digital/analog converter is the input of the in-phase/quadrature modulator. 
     
     
         13 . A system according to  claim 11 , where the output of the pulse shaping or the digital/analog converter is transmitted through a communications channel, the system further comprising a receiver comprising a sample and hold unit, a phase modulator or a frequency demodulator, a digital/analog converter and a low pass filter. 
     
     
         14 . A method for non-linear analog-to-digital conversion of an analog input signal into a digital output signal, the method being performed by a device comprising a Delta-Sigma, DS, converter, the DS converter comprising a subtraction unit, an integration unit, a quantization unit and a delay unit, the method comprises:
 performing a phase modulation in the feed forward branch on the DS converter of either the signal integrated by the integration unit or the signal quantized by the quantization unit, and performing a phase demodulation, by a phase demodulator in series with the delay unit, in the feedback branch of the DS converter, where the phase demodulation is the corresponding demodulation to the phase modulation, performing the inverse function of the phase modulation of the feed-forward branch or   performing a frequency modulation in the feed forward branch on the DS converter of either the signal integrated by the integration unit or the signal quantized by the quantization unit, and performing a frequency demodulation, by a frequency demodulator in series with the delay unit, in the feedback branch of the DS converter, where the frequency demodulation is the corresponding demodulation to the frequency modulation, performing the inverse function of the frequency modulation of the feed-forward branch.   
     
     
         15 . A non-transitory digital data storage medium encoding a machine-executable program of instructions to perform a method according to  claim 14 .